A seed used
in brachytherapy,
compared to a dime
Brachytherapy, or prostate seed implantation, is a type of radiation therapy
in which radioactive metallic seeds smaller than a grain of rice are permanently
placed inside the prostate gland. This therapy delivers a high dose of radiation
directly to the prostate gland and sometimes to the seminal vesicles. The seeds
give off their radiation slowly over several months and, within one year, their
radiation completely decays. The seeds can remain safely in place for the rest
of a man’s life. Brachytherapy is given with external radiation or by
itself, depending on the stage of cancer.
An x-ray of prostate seed implants
Brachytherapy works more effectively on small and moderately sized prostate glands. Men with very large prostates often undergo a 3- to 6-month course of hormone therapy to shrink the prostate prior to implantation.
Prior to implant surgery, you will need to have a transrectal ultrasound, a 5- to 15-minute outpatient procedure that uses sound waves to create a video image of the prostate gland. This allows the doctor to measure the size of the prostate, plan for the implantation and place the seed order.
A urologist and radiation oncologist work together to perform the implant. The urologist is responsible for the transrectal ultrasound and places a probe in your rectum to locate the prostate gland so it can be viewed on a monitor. A plastic template with tiny holes is placed against the perineum (the area between scrotum and anus). The radiation oncologist places thin, hollow needles through the grid and perineum and into the prostate gland. The radioactive seeds are put through the needles and planted in the prostate about .5 to 1 centimeter (a little less than ¼ - ½ inch) apart. The entire procedure lasts about 90 minutes.
The catheter may be left in place for a few days until prostate swelling subsides. Most patients are discharged three to four hours after the implant procedure.
There is little discomfort after the implant, except for some mild soreness in the perineal area lasting for one to two days. Sometimes some mild rectal bleeding or spotting will occur for about 24 hours in the area in which the needles were inserted. There may be a small amount of blood in the urine. This is normal and should stop in one to two days. Your doctor may instruct you to use an antibiotic cream on the surgical site for a few days following surgery.
For the first two days after surgery, you will need to avoid heavy lifting or hard physical activity. After that, you may return to your normal activity level. For several months after implantation, you will need to avoid exposing children and pregnant women to the radiation (your doctor can give you specific information on the precautions you should take).
A follow-up appointment will occur four to six weeks after surgery. It will include x-rays and a CT scan of the pelvis to indicate the positioning of the seeds and help determine the dose of radiation the prostate is receiving.
Unlike major surgery or daily radiation treatments, brachytherapy causes little interruption in your daily activities. In addition, this treatment usually preserves continence and causes erectile dysfunction less frequently than surgery or external beam radiation therapy.
The radiation can cause side effects, which may last for two to 12 months after the implant and will decrease gradually as the seeds lose their radioactivity. Side effects include discomfort during urination, urinary obstruction, and erectile dysfunction, all of which can be treated.